In typical control valves, a valve cage may provide guidance for a valve plug as the valve plug moves from a closed position in which the valve plug sealingly engages a valve seat to an open position in which the valve plug is disposed away from the valve seat. When the valve is in the open position, fluid flows from a valve inlet, passes through a passage between the valve seat and the valve plug, passes through the valve cage, and exits through a valve outlet. In addition to guiding the valve plug, a valve cage can also be used for additional functions, such as noise reduction.
Typical control valve cages usually include an annular cylindrical body having a plurality of co-planar, radial flow passages as a means to either control flow or add stability and/or robustness to the throttling plug. However, in applications that use a valve cage to condition and/or characterize the fluid flow, current technologies typically rely on drilling holes through the annular cylinder, using laminated through cut discs that are stacked and welded, brazed, or bolted together, or using laminated cast or etched discs that are stacked and welded, brazed or bolted together.
However, typical valve cages, especially high performance elements like anti-cavitation or noise attenuation designs, have many design restrictions to ensure performance. For example, proper outlet hole spacing is essential in many cases to ensure appropriate noise attenuation or energy dispersion. These designs usually have flow passages (inlet to outlet) that are fundamentally in the same plane. Although the flow passages can be any shape, length, diameter, with or without features like restrictions or expansions, these passages are largely co-planer and progress radially from the inner diameter of the valve cage to the outer diameter or form the outer diameter of the valve cage to the inner diameter, depending on the flow direction of the control valve. Therefore, to ensure the proper outlet spacing for the required high performance design, the inlets also must have a similar spacing, which can require a large travel distance of the valve plug between the fully closed and fully opened positions.